a. Field of the Invention
The present invention relates to a method for removing undesired components from the soil.
b. Description of the Prior Art
For a long time little or no attention has been paid to the consequences of dumping industrial waste, whether or not in special designated areas. In recent decennium increasing attention has been paid thereo. Attention was in the first place paid to pollution of surface waters, such as rivers ( especially the Rhine), lakes, such as the Great Lakes in the U.S.A., and also oceans and seas, in which latter case the pollutant is primarily oil. Of more recent date, attention has been paid to pollution of the soil by undesired components. Such components, which usually are poisonous for certain plants and/or animals, have been tackled in various manners, but none of the methods proposed hitherto have provided an attractive solution of the problem from the viewpoint of costs and logistics.
The most common method comprises digging of and digging out the polluted soil, which subsequently is dumped in an area specially designed for that purpose, or is treated. This usually requires transportation of large volumes of soil over relatively long distances, as far as the contaminated soil is concerned, as well as the supply of "clean" soil for refilling. The latter equally implies transportation of large volumes, though the distance may be relatively small under favorable conditions.
Another method comprises the immobilisation of the undesired components of the waste in the soil. As example to be mentioned is chemical bonding of heavy metals with chelateforming ion-exchanging resins, such as described in Dutch patent application No. 7508582. However, the heavy metals will still exert a toxic action.
Such heavy metals may also be bonded with a mercapto-s-triazine, such as mono-, di- or trimercapto-s-triazine, by adding that as such or in the form of a watersoluble salt to the soil, such as is described in Dutch patent application No. 7211368. In those cases the impurities remain in the soil in the bonded state into which they have been converted. Thus, there are no longer or at least to a much lesser extent detrimental.
In addition, many methods are known for introducing all kinds of materials into the soil, in particular fertilizers and other growth-promoting materials, as well as agents for preventing or combating diseases and soil strengthening means, but the removal of undesired components from the soil can not be derived therefrom.